CN114185384B - Transient enhancement circuit for low-power LDO (low dropout regulator) - Google Patents

Transient enhancement circuit for low-power LDO (low dropout regulator) Download PDF

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CN114185384B
CN114185384B CN202111241876.1A CN202111241876A CN114185384B CN 114185384 B CN114185384 B CN 114185384B CN 202111241876 A CN202111241876 A CN 202111241876A CN 114185384 B CN114185384 B CN 114185384B
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tube
mos
mos transistor
electrode
transistor
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CN114185384A (en
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张艺蒙
李宇飞
宋庆文
汤晓燕
张玉明
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Xidian University
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Xidian University
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    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices

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Abstract

The invention relates to a transient enhancement circuit for a low power consumption LDO, which comprises: the overshoot detection circuit is used for detecting the output voltage of the LDO and generating an undershoot detection signal and an overshoot detection signal when the output voltage of the LDO jumps; when the output voltage of the LDO undershoots, the negative slew rate enhancement control signal generation circuit generates a negative slew rate enhancement control signal according to an undershoot detection signal; when the output voltage of the LDO rises, the positive slew rate enhancement control signal generating circuit generates a positive slew rate enhancement control signal according to an uprush detection signal; the slew rate enhancement circuit controls the grid electrode of the adjusting tube of the LDO to be charged and discharged quickly according to the received negative slew rate enhancement control signal or positive slew rate enhancement control signal so as to realize the quick transient response of the LDO. The transient enhancement circuit has the advantages of simple structure, small area and extremely high cost performance in low-power LDO application.

Description

Transient enhancement circuit for low-power LDO (low dropout regulator)
Technical Field
The invention belongs to the technical field of integrated circuits, and particularly relates to a transient enhancement circuit for a low-power LDO (low dropout regulator).
Background
With the rapid development of wearable portable electronic devices and the wide application of digital-analog hybrid chips in such devices, power management chip design for such chips becomes more and more important. For the application scenario of such devices, the sustainable usage time is a very important indicator, and therefore, it is necessary to reduce the power consumption as much as possible.
Meanwhile, in the application of digital-analog hybrid chip, the output load current of LDO (low dropout regulator) often changes abruptly along with the operating state of the circuit. When the load current suddenly increases, the LDO cannot immediately respond to the sudden change of the load current and cannot output enough current, at the moment, partial current is provided by the output load capacitor, the output voltage firstly undershoots and then gradually recovers; when the load current suddenly drops, the LDO cannot immediately respond to the sudden change of the load current, excessive current is output, at the moment, part of current flows to the output load capacitor, the output voltage is firstly rushed up and then gradually recovered. Also in such applications, off-chip capacitors are often required to be output, thereby reducing the cost.
Therefore, when the output load current of the LDO suddenly changes, how to realize a design of the LDO that simultaneously achieves low power consumption, high transient response speed, no off-chip capacitance, and the like is a problem to be solved.
Disclosure of Invention
In order to solve the above problems in the prior art, the present invention provides a transient boost circuit for a low power LDO. The technical problem to be solved by the invention is realized by the following technical scheme:
the invention provides a transient enhancement circuit for a low-power LDO (low dropout regulator), which comprises: an overshoot detection circuit, a negative slew rate enhancement control signal generation circuit, a positive slew rate enhancement control signal generation circuit, and a slew rate enhancement circuit, wherein,
the input end of the overshoot detection circuit is connected with the output end of the LDO, the first output end of the overshoot detection circuit is connected with the input end of the negative slew rate enhancement control signal generation circuit, and the second output end of the overshoot detection circuit is connected with the input end of the positive slew rate enhancement control signal generation circuit;
the output end of the negative slew rate enhancement control signal generation circuit and the output end of the positive slew rate enhancement control signal generation circuit are both connected with the input end of the slew rate enhancement circuit; the output end of the slew rate enhancement circuit is connected with an adjusting tube of the LDO;
the overshoot detection circuit is used for detecting the output voltage of the LDO and generating an undershoot detection signal and an overshoot detection signal when the output voltage of the LDO jumps;
when the output voltage of the LDO undershoots, the negative slew rate enhancement control signal generation circuit generates a negative slew rate enhancement control signal according to the undershoot detection signal;
when the output voltage of the LDO rises, the positive slew rate enhancement control signal generating circuit generates a positive slew rate enhancement control signal according to the rising detection signal;
the slew rate enhancement circuit controls the grid electrode of the adjusting tube of the LDO to be charged and discharged quickly according to the received negative slew rate enhancement control signal or the positive slew rate enhancement control signal so as to realize the quick transient response of the LDO.
In one embodiment of the present invention, the overshoot detection circuit includes a first capacitor, a second capacitor, a first MOS transistor, a second MOS transistor, a third MOS transistor, and a fourth MOS transistor, wherein,
the source electrode of the first MOS tube inputs an external P tube bias voltage, and the grid electrode of the first MOS tube is respectively connected with the drain electrode of the first MOS tube and the grid electrode and the source electrode of the second MOS tube;
the source electrode of the fourth MOS tube inputs an external N tube bias voltage, and the grid electrode of the fourth MOS tube is respectively connected with the drain electrode of the fourth MOS tube and the grid electrode and the source electrode of the third MOS tube;
the drain electrode of the second MOS tube is used as a first output end of the overshoot detection circuit to output the undershoot detection signal; the drain electrode of the third MOS tube is used as a second output end of the overshoot detection circuit to output the overshoot detection signal;
the first capacitor is connected between the output end of the LDO and the drain electrode of the second MOS tube in series; the second capacitor is connected in series between the output end of the LDO and the drain electrode of the third MOS tube.
In an embodiment of the invention, when the regulating transistor of the LDO is a pMOS transistor, the negative slew rate enhancement control signal generating circuit includes: a third capacitor, a fifth MOS transistor, a sixth MOS transistor, a seventh MOS transistor, an eighth MOS transistor, a ninth pMOS transistor, a tenth pMOS transistor, an eleventh MOS transistor, a twelfth MOS transistor and a thirteenth MOS transistor, wherein,
the source electrode of the fifth MOS tube, the source electrode of the seventh MOS tube and the source electrode of the ninth pMOS tube are connected with a power supply end;
a grid electrode of the fifth MOS tube is connected with a first output end of the overshoot detection circuit, drain electrodes of the fifth MOS tube and the tenth pMOS tube are respectively connected with a drain electrode of the sixth MOS tube, a grid electrode of the seventh MOS tube, a grid electrode of the eighth MOS tube, a grid electrode of the tenth pMOS tube and a grid electrode of the twelfth MOS tube;
the grid electrode of the sixth MOS tube inputs the bias voltage of the external N tube;
the drain electrode of the seventh MOS tube is respectively connected with the drain electrode of the eighth MOS tube and the grid electrode of the eleventh MOS tube;
the grid electrode of the ninth pMOS tube inputs the bias voltage of the external P tube, and the drain electrode of the ninth pMOS tube is connected with the source electrode of the tenth pMOS tube;
the drain electrode of the tenth pMOS tube is respectively connected with the source electrode of the eleventh MOS tube, the drain electrode of the twelfth MOS tube and the grid electrode of the thirteenth MOS tube;
the drain electrode of the eleventh MOS transistor is respectively connected with the source electrode of the twelfth MOS transistor, the drain electrode of the thirteenth MOS transistor and the second input end of the slew rate enhancement circuit;
the third capacitor is connected between the drain electrode of the tenth pMOS tube and the grounding end in series;
and the source electrode of the sixth MOS tube, the source electrode of the eighth MOS tube and the source electrode of the thirteenth MOS tube are all connected with the grounding terminal.
In one embodiment of the present invention, the slew rate enhancement control signal generating circuit comprises a fourth capacitor, a fourteenth MOS transistor, a fifteenth MOS transistor, a sixteenth MOS transistor, a seventeenth MOS transistor, an eighteenth nMOS transistor, a nineteenth nMOS transistor, a twentieth MOS transistor, a twenty-first MOS transistor, and a twenty-twelfth MOS transistor, wherein,
the source electrode of the fourteenth MOS tube, the source electrode of the sixteenth MOS tube and the source electrode of the twenty second MOS tube are all connected with the power supply end;
the grid electrode of the fourteenth MOS tube inputs the bias voltage of the external P tube, and the drain electrode is respectively connected with the drain electrode of the fifteenth MOS tube, the grid electrode of the sixteenth MOS tube, the grid electrode of the seventeenth MOS tube, the grid electrode of the eighteenth nMOS tube and the grid electrode of the twentieth MOS tube;
the grid electrode of the fifteenth MOS tube is connected with the second output end of the overshoot detection circuit;
the drain electrode of the sixteenth MOS tube is respectively connected with the drain electrode of the seventeenth MOS tube and the grid electrode of the twenty-first MOS tube;
the grid electrode of the nineteenth nMOS tube inputs the bias voltage of the external N tube, and the drain electrode of the nineteenth nMOS tube is connected with the source electrode of the eighteenth nMOS tube;
the drain electrode of the eighteenth nMOS tube is respectively connected with the source electrode of the twentieth MOS tube, the drain electrode of the twenty-first MOS tube and the grid electrode of the twenty-second MOS tube;
the drain electrode of the twentieth MOS tube is respectively connected with the source electrode of the twenty-first MOS tube, the drain electrode of the twenty-second MOS tube and the first input end of the slew rate enhancement circuit;
the fourth capacitor is connected between the drain electrode of the eighteenth nMOS tube and the power supply end in series;
and the source electrode of the fifteenth MOS tube, the source electrode of the seventeenth MOS tube and the source electrode of the nineteenth nMOS tube are all connected with the grounding end.
In an embodiment of the present invention, when the regulating transistor of the LDO is an nMOS transistor, the negative slew rate enhancement control signal generating circuit includes: a third capacitor, a fifth MOS transistor, a sixth MOS transistor, a seventh MOS transistor, an eighth MOS transistor, a ninth nMOS transistor, a tenth nMOS transistor, an eleventh MOS transistor, a twelfth MOS transistor and a thirteenth MOS transistor,
the source electrode of the fifth MOS tube, the source electrode of the seventh MOS tube and the source electrode of the thirteenth MOS tube are all connected with a power supply end;
the grid electrode of the fifth MOS tube is connected with the first output end of the overshoot detection circuit, the drain electrodes of the fifth MOS tube and the eighth MOS tube are respectively connected with the drain electrode of the sixth MOS tube, the grid electrode of the seventh MOS tube, the grid electrode of the eighth MOS tube and the grid electrode of the twelfth MOS tube;
the grid electrode of the sixth MOS tube inputs the bias voltage of the external N tube;
the drain electrode of the seventh MOS tube is respectively connected with the drain electrode of the eighth MOS tube, the grid electrode of the ninth nMOS tube and the grid electrode of the eleventh MOS tube;
the grid electrode of the tenth nMOS tube inputs the bias voltage of the external N tube, and the drain electrode of the tenth nMOS tube is connected with the source electrode of the ninth nMOS tube;
the drain electrode of the ninth nMOS tube is respectively connected with the source electrode of the eleventh MOS tube, the drain electrode of the twelfth MOS tube and the gate electrode of the thirteenth MOS tube;
the drain electrode of the eleventh MOS transistor is respectively connected with the source electrode of the twelfth MOS transistor, the drain electrode of the thirteenth MOS transistor and the first input end of the slew rate enhancement circuit;
the third capacitor is connected in series between the drain electrode of the ninth nMOS transistor and the power supply end;
and the source electrode of the sixth MOS transistor, the source electrode of the eighth MOS transistor and the source electrode of the tenth nMOS transistor are all connected with the grounding terminal.
In one embodiment of the present invention, the slew rate enhancement control signal generating circuit includes a fourth capacitor, a fourteenth MOS transistor, a fifteenth MOS transistor, a sixteenth MOS transistor, a seventeenth MOS transistor, an eighteenth pMOS transistor, a nineteenth pMOS transistor, a twentieth MOS transistor, a twenty-first MOS transistor, and a twenty-twelfth MOS transistor,
the source electrode of the fourteenth MOS tube, the source electrode of the sixteenth MOS tube and the source electrode of the eighteenth pMOS tube are all connected with the power supply end;
the grid electrode of the fourteenth MOS tube inputs the bias voltage of the external P tube, and the drain electrode of the fourteenth MOS tube is respectively connected with the drain electrode of the fifteenth MOS tube, the grid electrode of the sixteenth MOS tube, the grid electrode of the seventeenth MOS tube and the grid electrode of the twentieth MOS tube;
the grid electrode of the fifteenth MOS tube is connected with the second output end of the overshoot detection circuit;
the drain electrode of the sixteenth MOS tube is respectively connected with the drain electrode of the seventeenth MOS tube, the grid electrode of the nineteenth pMOS tube and the grid electrode of the twenty-first MOS tube;
the grid electrode of the eighteenth pMOS tube inputs the bias voltage of the external P tube, and the drain electrode of the eighteenth pMOS tube is connected with the source electrode of the nineteenth pMOS tube;
the drain electrode of the nineteenth pMOS tube is respectively connected with the source electrode of the twentieth MOS tube, the drain electrode of the twenty-first MOS tube and the grid electrode of the twenty-second MOS tube;
the drain electrode of the twentieth MOS tube is respectively connected with the source electrode of the twenty-first MOS tube, the drain electrode of the twenty-second MOS tube and the second input end of the slew rate enhancement circuit;
the fourth capacitor is connected between the drain electrode of the nineteenth pMOS tube and the grounding end in series;
and the source electrode of the fifteenth MOS tube, the source electrode of the seventeenth MOS tube and the source electrode of the twenty-second MOS tube are all connected with the grounding terminal.
In one embodiment of the present invention, the slew rate enhancement circuit comprises a twenty-third MOS transistor and a twenty-fourth MOS transistor, wherein,
the source electrode of the twenty-third MOS tube is connected with the power supply end, the grid electrode of the twenty-third MOS tube is used as a first input end of the slew rate enhancement circuit, and the drain electrode of the twenty-third MOS tube is connected with the drain electrode of the twenty-fourth MOS tube and the grid electrode of the regulating tube of the LDO respectively;
and the source electrode of the twenty-fourth MOS transistor is connected with the grounding end, and the grid electrode of the twenty-fourth MOS transistor is used as a second input end of the slew rate enhancement circuit.
Compared with the prior art, the invention has the beneficial effects that:
1. the transient enhancement circuit for the low-power LDO does not work when the circuit is stable, has extremely low static power consumption, can provide an instantaneous charge-discharge current only when the output load jumps, has a simple circuit structure, occupies a small area, and has extremely high cost performance in the application of the low-power LDO.
2. The transient enhancement circuit for the low-power LDO provided by the invention utilizes the charge-discharge characteristic that a capacitor is connected with a diode-connected MOS (metal oxide semiconductor) tube to generate a slew rate enhancement control signal, can generate a very large charge-discharge current at the moment of sudden change of a load, and can be used for charging and discharging a gate of an adjusting tube to improve the transient response speed of the LDO.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are specifically described below with reference to the accompanying drawings.
Drawings
FIG. 1 is a block diagram of a transient enhancement circuit for a low-power LDO according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of a transient enhancement circuit for a low power LDO when an LDO regulating tube provided by an embodiment of the invention is a pMOS;
FIG. 3 is a circuit diagram of a transient enhancement circuit for a low power LDO when the LDO regulator is an nMOS according to an embodiment of the present invention;
FIG. 4 is a simulated waveform diagram of a transient enhancement circuit for a low power LDO when the LDO regulator is a pMOS according to the embodiment of the present invention;
FIG. 5 is a simulated waveform diagram of the transient enhancement circuit for a low power LDO when the LDO regulating tube provided by the embodiment of the invention is nMOS.
Detailed Description
To further illustrate the technical means and effects of the present invention for achieving the predetermined objects, a transient boost circuit for a low power LDO according to the present invention is described in detail below with reference to the accompanying drawings and the detailed description.
The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description of the embodiments, which is to be read in connection with the accompanying drawings. The technical means and effects of the present invention adopted to achieve the predetermined purpose can be more deeply and specifically understood through the description of the specific embodiments, however, the attached drawings are provided for reference and description only and are not used for limiting the technical scheme of the present invention.
Example one
Referring to fig. 1, fig. 1 is a block diagram of a transient enhancement circuit for a low power LDO according to an embodiment of the present invention, and as shown in the figure, the transient enhancement circuit for a low power LDO according to the embodiment includes: the overshoot detection circuit, the negative slew rate enhancement control signal generation circuit, the positive slew rate enhancement control signal generation circuit and the slew rate enhancement circuit. The input end of the overshoot detection circuit is connected with the output end of the LDO, the first output end of the overshoot detection circuit is connected with the input end of the negative slew rate enhancement control signal generation circuit, and the second output end of the overshoot detection circuit is connected with the input end of the positive slew rate enhancement control signal generation circuit; the output end of the negative slew rate enhancement control signal generation circuit and the output end of the positive slew rate enhancement control signal generation circuit are both connected with the input end of the slew rate enhancement circuit; the output end of the slew rate enhancement circuit is connected with an adjusting tube of the LDO.
In this embodiment, the overshoot detection circuit is configured to detect an output voltage of the LDO, and generate an undershoot detection signal VSEN _ P and an overshoot detection signal VSEN _ N when the output voltage of the LDO jumps; when the output voltage of the LDO is undershot, the negative slew rate enhancement control Signal generation circuit generates a negative slew rate enhancement control Signal Under _ Signal according to an undershoot detection Signal VSEN _ P; when the output voltage of the LDO is uprushed, the positive slew rate enhancement control Signal generating circuit generates a positive slew rate enhancement control Signal Over _ Signal according to an uprush detection Signal VSEN _ N; the slew rate enhancement circuit controls the grid electrode of the adjusting tube of the LDO to be charged and discharged quickly according to the received negative slew rate enhancement control Signal Under _ Signal or positive slew rate enhancement control Signal Over _ Signal so as to realize the quick transient response of the LDO.
The transient enhancement circuit for the low-power LDO of this embodiment does not work when the circuit is stable, has extremely low static power consumption, only when the jump takes place at output load, just can provide an instantaneous charge-discharge current, and circuit structure is simple, and the area occupied is little, in low-power LDO uses, has high price/performance ratio. Moreover, by utilizing the charge-discharge characteristic that the capacitor is connected with the diode-connected MOS tube, the generated slew rate enhancement control signal can generate a very large charge-discharge current at the moment when the load suddenly changes, so as to adjust the charge-discharge of the tube grid and improve the transient response speed of the LDO.
Example two
A specific circuit structure of the transient enhancement circuit for a low power LDO of this embodiment will be described when the tuning transistor of the LDO is a pMOS.
Referring to fig. 2, fig. 2 is a circuit diagram of a transient enhancement circuit for a low power LDO when the LDO regulator is a pMOS according to an embodiment of the present invention. As shown in the figure, in the present embodiment, the overshoot detection circuit includes a first capacitor C1, a second capacitor C2, a first MOS transistor M1, a second MOS transistor M2, a third MOS transistor M3, and a fourth MOS transistor M4.
In this embodiment, the first MOS transistor M1 and the second MOS transistor M2 are both pMOS transistors, and the third MOS transistor M3 and the fourth MOS transistor M4 are both nMOS transistors.
The source electrode of the first MOS tube M1 inputs an external P tube BIAS voltage V _ BIAS _ P, and the grid electrode is respectively connected with the drain electrode of the first MOS tube M1 and the grid electrode and the source electrode of the second MOS tube M2; the source electrode of the fourth MOS transistor M4 is input with an external N-transistor BIAS voltage V _ BIAS _ N, and the grid electrode of the fourth MOS transistor M4 is respectively connected with the drain electrode of the fourth MOS transistor M4 and the grid electrode and the source electrode of the third MOS transistor M3; the drain electrode of the second MOS tube M2 is used as a first output end of the overshoot detection circuit to output an undershoot detection signal VSEN _ P; the drain electrode of the third MOS transistor M3 serves as a second output end of the overshoot detection circuit to output an overshoot detection signal VSEN _ N; the first capacitor C1 is connected in series between the output end of the LDO and the drain electrode of the second MOS tube M2; the second capacitor C2 is connected in series between the output end of the LDO and the drain of the third MOS transistor M3.
Further, the negative slew rate enhancement control signal generation circuit includes: a third capacitor C3, a fifth MOS transistor M5, a sixth MOS transistor M6, a seventh MOS transistor M7, an eighth MOS transistor M8, a ninth pMOS transistor Mp9, a tenth pMOS transistor Mp10, an eleventh MOS transistor M11, a twelfth MOS transistor M12, and a thirteenth MOS transistor M13.
In this embodiment, the fifth MOS transistor M5, the seventh MOS transistor M7, and the eleventh MOS transistor M11 are pMOS transistors, and the sixth MOS transistor M6, the eighth MOS transistor M8, the twelfth MOS transistor M12, and the thirteenth MOS transistor M13 are nMOS transistors.
The source electrode of the fifth MOS transistor M5, the source electrode of the seventh MOS transistor M7 and the source electrode of the ninth pMOS transistor Mp9 are all connected with a power supply end VDD; a grid electrode of the fifth MOS transistor M5 is connected with the first output end of the overshoot detection circuit, and drain electrodes of the fifth MOS transistor M5 and the tenth pMOS transistor M5 are respectively connected with a drain electrode of the sixth MOS transistor M6, a grid electrode of the seventh MOS transistor M7, a grid electrode of the eighth MOS transistor M8, a grid electrode of the tenth pMOS transistor Mp10 and a grid electrode of the twelfth MOS transistor M12; the grid electrode of the sixth MOS tube M6 is input with an external N tube BIAS voltage V _ BIAS _ N; the drain electrode of the seventh MOS transistor M7 is connected to the drain electrode of the eighth MOS transistor M8 and the gate electrode of the eleventh MOS transistor M11, respectively.
The grid electrode of the ninth pMOS tube Mp9 is input with an external P tube BIAS voltage V _ BIAS _ P, and the drain electrode is connected with the source electrode of the tenth pMOS tube Mp 10; the drain electrode of the tenth pMOS transistor Mp10 is connected to the source electrode of the eleventh MOS transistor M11, the drain electrode of the twelfth MOS transistor M12 and the gate electrode of the thirteenth MOS transistor M13, respectively; the drain of the eleventh MOS transistor M11 is connected to the source of the twelfth MOS transistor M12, the drain of the thirteenth MOS transistor M13, and the second input of the slew rate enhancement circuit, respectively.
The third capacitor C3 is connected in series between the drain of the tenth pMOS transistor Mp10 and the ground GND; the source electrode of the sixth MOS transistor M6, the source electrode of the eighth MOS transistor M8, and the source electrode of the thirteenth MOS transistor M13 are all connected to the ground GND.
In this embodiment, when the output voltage of the LDO undershoots, the drain of the eleventh MOS transistor M11 serves as the output terminal of the negative slew rate enhancement control Signal generation circuit, and outputs the negative slew rate enhancement control Signal Under _ Signal.
Further, the slew rate enhancement control signal generation circuit includes a fourth capacitor C4, a fourteenth MOS transistor M14, a fifteenth MOS transistor M15, a sixteenth MOS transistor M16, a seventeenth MOS transistor M17, an eighteenth nMOS transistor Mn18, a nineteenth nMOS transistor Mn19, a twentieth MOS transistor M20, a twenty-first MOS transistor M21, and a twenty-twelfth MOS transistor M22.
In this embodiment, the fourteenth MOS transistor M14, the sixteenth MOS transistor M16, the twentieth MOS transistor M20, and the twenty-twelfth MOS transistor M22 are all pMOS transistors, and the fifteenth MOS transistor M15, the seventeenth MOS transistor M17, and the twenty-first MOS transistor M21 are all nMOS transistors.
The source electrode of the fourteenth MOS transistor M14, the source electrode of the sixteenth MOS transistor M16 and the source electrode of the twenty-second MOS transistor M22 are all connected with a power supply end VDD; the grid electrode of the fourteenth MOS tube M14 inputs an external P tube BIAS voltage V _ BIAS _ P, and the drain electrode is respectively connected with the drain electrode of the fifteenth MOS tube M15, the grid electrode of the sixteenth MOS tube M16, the grid electrode of the seventeenth MOS tube M17, the grid electrode of the eighteenth nMOS tube Mn18 and the grid electrode of the twentieth MOS tube M20; the grid electrode of the fifteenth MOS tube M15 is connected with the second output end of the overshoot detection circuit; the drain electrode of the sixteenth MOS transistor M16 is respectively connected with the drain electrode of the seventeenth MOS transistor M17 and the gate electrode of the twenty-first MOS transistor M21; the gate of the nineteenth nMOS tube Mn19 is input with an external N tube BIAS voltage V _ BIAS _ N, and the drain is connected with the source of the eighteenth nMOS tube Mn 18.
The drain electrode of the eighteenth nMOS transistor Mn18 is respectively connected with the source electrode of the twentieth MOS transistor M20, the drain electrode of the twenty-first MOS transistor M21 and the gate electrode of the twenty-second MOS transistor M22; the drain electrode of the twentieth MOS transistor M20 is respectively connected to the source electrode of the twenty-first MOS transistor M21, the drain electrode of the twenty-second MOS transistor M22 and the first input end of the slew rate enhancement circuit; the fourth capacitor C4 is connected in series between the drain of the eighteenth nMOS transistor Mn18 and the power supply terminal VDD; the source of the fifteenth MOS transistor M15, the source of the seventeenth MOS transistor M17, and the source of the nineteenth nMOS transistor Mn19 are all connected to the ground GND.
In this embodiment, when the output voltage of the LDO is overshot, the drain of the twentieth MOS transistor M20 serves as the output terminal of the slew rate enhancement control Signal generation circuit, and outputs the slew rate enhancement control Signal Over _ Signal.
Further, the slew rate enhancement circuit comprises a twenty-third MOS transistor M23 and a twenty-fourth MOS transistor M24. In this embodiment, the twenty-third MOS transistor M23 is a pMOS transistor, and the twenty-fourth MOS transistor M24 is an nMOS transistor.
The source electrode of the twenty-third MOS transistor M23 is connected with a power supply end VDD, the grid electrode is used as a first input end of the slew rate enhancement circuit, and the drain electrode is connected with the drain electrode of the twenty-fourth MOS transistor M24 and the grid electrode of the regulating transistor of the LDO respectively; the source of the twenty-fourth MOS transistor M24 is connected to the ground GND, and the gate is used as the second input terminal of the slew rate enhancement circuit.
Further, a principle of the transient enhancement circuit when the LDO regulator of the present embodiment is a pMOS will be described.
In the overshoot detection circuit, the first MOS transistor M1, the second MOS transistor M2, the third MOS transistor M3, and the fourth MOS transistor M4 respectively constitute two resistors with a large resistance value, and one end of each resistor is respectively connected to an external P transistor BIAS voltage V _ BIAS _ P and an external N transistor BIAS voltage V _ BIAS _ N, so as to provide a fixed direct current BIAS for the fifth MOS transistor M5 and the fifteenth MOS transistor M15. One end of the first capacitor C1 and one end of the second capacitor C2, which are used as coupling capacitors, are connected to the output of the LDO, and the other end of the first capacitor C1 and one end of the second capacitor C2 are respectively connected to the grids of the fifth MOS transistor M5 and the fifteenth MOS transistor M15.
In a steady state, in the negative slew rate enhancement control Signal generation circuit, a transmission gate formed by an eleventh MOS transistor M11 and a twelfth MOS transistor M12 is closed, a tenth pMOS transistor Mp10 is opened, a third capacitor C3 is fully charged, a gate of a thirteenth MOS transistor M13, that is, a high terminal of the third capacitor C3 is at a high level, a negative slew rate enhancement control Signal Under _ Signal output by the negative slew rate enhancement control Signal generation circuit is at a low level, and a twenty-fourth MOS transistor M24 is closed.
When the output load current of the LDO is suddenly increased, an undershoot occurs in the output voltage of the LDO, at this time, an undershoot signal is coupled to the gate of the fifth MOS transistor M5 through the first capacitor C1, that is, the gate voltage of the fifth MOS transistor M5 is decreased, because the gate voltage of the sixth MOS transistor M6 is fixed by the BIAS voltage V _ BIAS _ N of the external N transistor. Therefore, the output of the current comparator composed of the fifth MOS transistor M5 and the sixth MOS transistor M6 will be inverted from low to high, the transmission gate composed of the eleventh MOS transistor M11 and the twelfth MOS transistor M12 will be opened, and the tenth pMOS transistor Mp10 will be closed. The third capacitor C3 and the thirteenth MOS transistor M13 form a capacitor-diode connection, the third capacitor C3 starts to discharge through the thirteenth MOS transistor M13, and generates a control Signal synchronized with the LDO undershoot Signal, i.e., a negative slew rate enhancement control Signal undersignal, by using the discharge characteristics of the capacitor-diode connection, at this time, the gate of the twenty-fourth MOS transistor M24 is opened to discharge to the gate of the adjustment transistor MP of the LDO, and the magnitude of the discharge current is determined by the negative slew rate enhancement control Signal undersignal and synchronized with the undershoot Signal output by the LDO.
On the other hand, in a steady state, in the positive slew rate enhancement control Signal generation circuit, the transmission gate formed by the twentieth MOS transistor M20 and the twenty-first MOS transistor M21 is closed, the eighteenth nMOS transistor Mn18 is opened, the fourth capacitor C4 is fully charged, the gate of the twenty-second MOS transistor M22, that is, the lower end of the fourth capacitor C4, is at a low level, the positive slew rate enhancement control Signal Over _ Signal output by the positive slew rate enhancement control Signal generation circuit is at a high level, and the twenty-third MOS transistor M23 is closed.
When the output load current of the LDO suddenly decreases, the output voltage of the LDO may overshoot, and at this time, the overshoot signal is coupled to the gate of the fifteenth MOS transistor M15 through the second capacitor C2, that is, the gate voltage of the fifteenth MOS transistor M15 rises, because the gate voltage of the fourteenth MOS transistor M14 is fixed by the BIAS voltage V _ BIAS _ P of the external P-type transistor. Therefore, the output of the current comparator composed of the fifteenth MOS transistor M15 and the fourteenth MOS transistor M14 will be inverted from high to low, the transmission gate composed of the twentieth MOS transistor M20 and the twenty-first MOS transistor M21 will be opened, and the eighteenth nMOS transistor Mn18 will be closed. The fourth capacitor C4 and the twenty-second MOS transistor M22 form a capacitor-diode connection, and the fourth capacitor C4 starts to discharge through the diode-connected twenty-second MOS transistor M22. And generating a control Signal synchronous with the overshoot Signal of the LDO, namely a positive slew rate enhanced control Signal Over _ Signal, by utilizing the discharge characteristic of a capacitor and a diode connection method, wherein at the moment, the grid electrode of the twenty-third MOS transistor M23 is opened to charge the grid electrode of the adjusting transistor MP of the LDO, and the magnitude of the charging current is determined by the positive slew rate enhanced control Signal Over _ Signal and is synchronous with the overshoot Signal output by the LDO.
Referring to fig. 4, fig. 4 is a waveform diagram of a simulation of a transient enhancement circuit for a low power LDO when the LDO regulator is a pMOS according to an embodiment of the present invention. Experimental conditions were LDO output load switching between 200uA and 20mA with a switching time of 1ns.
It can be seen from the figure that, when the output load current suddenly increases, the LDO output voltage has an undershoot voltage, the transient enhancement circuit generates an Under _ Signal, and the twenty-four MOS transistors M24 are turned on and gradually turned off as the Under _ Signal becomes smaller, so as to accelerate discharge of the gate of the regulating transistor of the LDO. Similarly, when the output load current suddenly drops, the output voltage of the LDO has an overshoot voltage, the transient enhancement circuit generates an Over _ Signal, and the thirteenth MOS transistor M23 is turned on and gradually turned off as the Over _ Signal becomes larger, so as to accelerate charging of the gate of the adjustment transistor of the LDO.
The transient enhancement circuit of the embodiment generates gradually attenuated and gradually increased Under _ Signal and Over _ Signal signals respectively when the output load current suddenly increases or suddenly decreases, and is used for controlling the charging and discharging of the slew rate enhancement circuit to the adjusting tube. Since it is not working in steady state, the quiescent current is very low. When the circuit is in a dynamic state, the circuit is only operated for a period of time, so that the power consumption of the circuit is greatly reduced while the transient response speed is enhanced.
EXAMPLE III
A specific circuit structure of the transient enhancement circuit for a low power LDO of this embodiment will be described when the tuning transistor of the LDO is nMOS.
Referring to fig. 3, fig. 3 is a circuit diagram of a transient enhancement circuit for a low power LDO when the LDO regulator is nMOS according to an embodiment of the present invention. As shown in the figure, the overshoot detection circuit in this embodiment has the same structure as the overshoot detection circuit in the second embodiment, and is not described herein again.
In this embodiment, the negative slew rate enhancement control signal generating circuit includes: a third capacitor C3, a fifth MOS transistor M5, a sixth MOS transistor M6, a seventh MOS transistor M7, an eighth MOS transistor M8, a ninth nMOS transistor Mn9, a tenth nMOS transistor Mn10, an eleventh MOS transistor M11, a twelfth MOS transistor M12, and a thirteenth MOS transistor M13.
In this embodiment, the fifth MOS transistor M5, the seventh MOS transistor M7, the eleventh MOS transistor M11, and the thirteenth MOS transistor M13 are all pMOS transistors, and the sixth MOS transistor M6, the eighth MOS transistor M8, and the twelfth MOS transistor M12 are all nMOS transistors.
The source electrode of the fifth MOS transistor M5, the source electrode of the seventh MOS transistor M7 and the source electrode of the thirteenth MOS transistor M13 are all connected with a power supply end VDD; the grid electrode of the fifth MOS transistor M5 is connected with the first output end of the overshoot detection circuit, and the drain electrodes are respectively connected with the drain electrode of the sixth MOS transistor M6, the grid electrode of the seventh MOS transistor M7, the grid electrode of the eighth MOS transistor M8 and the grid electrode of the twelfth MOS transistor M12; the grid electrode of the sixth MOS transistor M6 is input with an external N-transistor BIAS voltage V _ BIAS _ N; the drain electrode of the seventh MOS transistor M7 is connected to the drain electrode of the eighth MOS transistor M8, the gate electrode of the ninth nMOS transistor Mn9, and the gate electrode of the eleventh MOS transistor M11, respectively.
The grid electrode of the tenth nMOS tube Mn10 inputs an external N tube BIAS voltage V _ BIAS _ N, and the drain electrode is connected with the source electrode of the ninth nMOS tube Mn 9; the drain electrode of the ninth nMOS transistor Mn9 is respectively connected with the source electrode of the eleventh MOS transistor M11, the drain electrode of the twelfth MOS transistor M12 and the gate electrode of the thirteenth MOS transistor M13; the drain of the eleventh MOS transistor M11 is connected to the source of the twelfth MOS transistor M12, the drain of the thirteenth MOS transistor M13, and the first input of the slew rate enhancement circuit, respectively.
The third capacitor C3 is connected in series between the drain of the ninth nMOS transistor Mn9 and the power supply terminal VDD; the source electrode of the sixth MOS transistor M6, the source electrode of the eighth MOS transistor M8, and the source electrode of the tenth nMOS transistor Mn10 are all connected to the ground GND.
In this embodiment, when the output voltage of the LDO undershoots, the drain of the eleventh MOS transistor M11 serves as the output terminal of the negative slew rate enhancement control Signal generation circuit, and outputs the negative slew rate enhancement control Signal Under _ Signal.
Further, the positive slew rate enhancement control signal generation circuit includes a fourth capacitor C4, a fourteenth MOS transistor M14, a fifteenth MOS transistor M15, a sixteenth MOS transistor M16, a seventeenth MOS transistor M17, an eighteenth pMOS transistor Mp18, a nineteenth pMOS transistor Mp19, a twentieth MOS transistor M20, a twenty-first MOS transistor M21, and a twenty-second MOS transistor M22.
In this embodiment, the fourteenth MOS transistor M14, the sixteenth MOS transistor M16, and the twentieth MOS transistor M20 are pMOS transistors, and the fifteenth MOS transistor M15, the seventeenth MOS transistor M17, the twenty-first MOS transistor M21, and the twenty-twelfth MOS transistor M22 are nMOS transistors.
The source electrode of the fourteenth MOS tube M14, the source electrode of the sixteenth MOS tube M16 and the source electrode of the eighteenth pMOS tube Mp18 are all connected with a power supply end VDD; a grid electrode of the fourteenth MOS transistor M14 is input with an external P-type transistor BIAS voltage V _ BIAS _ P, and a drain electrode of the fourteenth MOS transistor M14 is respectively connected with a drain electrode of the fifteenth MOS transistor M15, a grid electrode of the sixteenth MOS transistor M16, a grid electrode of the seventeenth MOS transistor M17 and a grid electrode of the twentieth MOS transistor M20; the grid electrode of the fifteenth MOS tube M15 is connected with the second output end of the overshoot detection circuit; the drain electrode of the sixteenth MOS transistor M16 is connected to the drain electrode of the seventeenth MOS transistor M17, the gate electrode of the nineteenth pMOS transistor Mp19, and the gate electrode of the twenty-first MOS transistor M21, respectively.
The grid electrode of the eighteenth pMOS tube Mp18 is input with an external P tube BIAS voltage V _ BIAS _ P, and the drain electrode is connected with the source electrode of the nineteenth pMOS tube Mp 19; the drain electrode of the nineteenth pMOS tube Mp19 is respectively connected with the source electrode of the twentieth MOS tube M20, the drain electrode of the twenty-first MOS tube M21 and the gate electrode of the twenty-second MOS tube M22; the drain of the twentieth MOS transistor M20 is connected to the source of the twenty-first MOS transistor M21, the drain of the twenty-second MOS transistor M22, and the second input terminal of the slew rate enhancement circuit, respectively.
The fourth capacitor C4 is connected in series between the drain of the nineteenth pMOS transistor Mp19 and the ground GND, and the source of the fifteenth MOS transistor M15, the source of the seventeenth MOS transistor M17, and the source of the twenty second MOS transistor M22 are all connected to the ground GND.
In this embodiment, when the output voltage of the LDO is overshooting, the drain of the twentieth MOS transistor M20 serves as the output terminal of the slew rate enhancement control Signal generation circuit, and outputs the slew rate enhancement control Signal Over _ Signal.
Further, the slew rate enhancement circuit has the same structure as the slew rate enhancement circuit in the second embodiment, and is not described herein again.
Further, the principle of the transient enhancement circuit when the LDO regulator of the present embodiment is nMOS will be explained.
In the overshoot detection circuit, a first MOS transistor M1, a second MOS transistor M2, a third MOS transistor M3, and a fourth MOS transistor M4 respectively constitute two resistors with a very large resistance value, and one end of each resistor is respectively connected with an external P transistor BIAS voltage V _ BIAS _ P and an external N transistor BIAS voltage V _ BIAS _ N, so as to provide a fixed direct current BIAS for a fifth MOS transistor M5 and a fifteenth MOS transistor M15. One end of the first capacitor C1 and one end of the second capacitor C2, which are used as coupling capacitors, are connected to the output of the LDO, and the other end of the first capacitor C1 and one end of the second capacitor C2 are respectively connected to the grids of the fifth MOS transistor M5 and the fifteenth MOS transistor M15.
In a steady state, in the negative slew rate enhancement control Signal generation circuit, the transmission gate formed by the eleventh MOS transistor M11 and the twelfth MOS transistor M12 is closed, the ninth nMOS transistor Mn9 is opened, the third capacitor C3 is fully charged, the gate of the thirteenth MOS transistor M13, that is, the low end of the third capacitor C3 is at a low level, the negative slew rate enhancement control Signal Under _ Signal output by the negative slew rate enhancement control Signal generation circuit is at a high level, and the twenty-third MOS transistor M23 is closed.
When the output load current of the LDO suddenly increases, an undershoot occurs in the output voltage of the LDO, at this time, an undershoot signal is coupled to the gate of the fifth MOS transistor M5 through the first capacitor C1, that is, the gate voltage of the fifth MOS transistor M5 decreases, because the gate voltage of the sixth MOS transistor M6 is fixed by the BIAS voltage V _ BIAS _ N of the external N transistor. Therefore, the output of the current comparator composed of the fifth MOS transistor M5 and the sixth MOS transistor M6 will be inverted from low to high, the transmission gate composed of the eleventh MOS transistor M11 and the twelfth MOS transistor M12 will be opened, and the ninth nMOS transistor Mn9 will be closed. The third capacitor C3 and the thirteenth MOS transistor M13 form a capacitor-diode connection, the third capacitor C3 starts to discharge through the thirteenth MOS transistor M13 connected to a diode, and generates a control Signal synchronized with the LDO undershoot Signal, i.e., a negative slew rate enhancement control Signal Under _ Signal, by using the discharge characteristic of the capacitor-diode connection, at this time, the gate of the twenty-third MOS transistor M23 is opened to charge the gate of the adjustment transistor MN of the LDO, and the magnitude of the discharge current is determined by the negative slew rate enhancement control Signal Under _ Signal and synchronized with the undershoot Signal output by the LDO.
On the other hand, in a steady state, in the slew rate enhancement control Signal generation circuit, the transmission gate formed by the twentieth MOS transistor M20 and the twenty-first MOS transistor M21 is closed, the nineteenth pMOS transistor Mp19 is opened, the fourth capacitor C4 is fully charged, the gate of the twelfth MOS transistor M22, that is, the high terminal of the fourth capacitor C4 is at a high level, the slew rate enhancement control Signal Over _ Signal output by the slew rate enhancement control Signal generation circuit is at a low level, and the twenty-fourth MOS transistor M24 is closed.
When the output load current of the LDO suddenly decreases, the output voltage of the LDO may overshoot, and at this time, the overshoot signal is coupled to the gate of the fifteenth MOS transistor M15 through the second capacitor C2, that is, the gate voltage of the fifteenth MOS transistor M15 rises, because the gate voltage of the fourteenth MOS transistor M14 is fixed by the BIAS voltage V _ BIAS _ P of the external P-type transistor. Therefore, the output of the current comparator composed of the fifteenth MOS transistor M15 and the fourteenth MOS transistor M14 will be inverted from high to low, the transmission gate composed of the twentieth MOS transistor M20 and the twenty-first MOS transistor M21 will be opened, and the nineteenth pMOS transistor Mp19 will be closed. The fourth capacitor C4 and the twenty-second MOS transistor M22 form a capacitor-diode connection, and the fourth capacitor C4 starts to discharge through the diode-connected twenty-second MOS transistor M22. And generating a control Signal synchronous with the LDO undershoot Signal, namely a positive slew rate enhanced control Signal Over _ Signal, by utilizing the discharge characteristic of a capacitor and diode connection method, wherein at the moment, the grid electrode of the twenty-fourth MOS tube M24 is opened to discharge for the grid electrode of the adjusting tube MN of the LDO, and the magnitude of the discharge current is determined by the positive slew rate enhanced control Signal Over _ Signal and is synchronous with the overshoot Signal output by the LDO.
Referring to fig. 5, fig. 5 is a simulated waveform diagram of the transient enhancement circuit for a low power consumption LDO when the LDO regulator is an nMOS according to an embodiment of the present invention. The experimental conditions were that the LDO output load was switched between 200uA and 20mA with a switching time of 1ns.
It can be seen from the figure that, when the output load current suddenly increases, the LDO output voltage has an undershoot voltage, the transient enhancement circuit generates an Under _ Signal, and the thirteenth MOS transistor M23 is turned on and gradually turned off as the Under _ Signal becomes smaller, so as to accelerate charging of the gate of the regulating transistor of the LDO. Similarly, when the output load current suddenly drops, the output voltage of the LDO has an overshoot voltage, the transient enhancement circuit generates an Over _ Signal, and the twenty-four MOS transistor M24 is turned on and gradually turned off as the Over _ Signal becomes larger, so as to accelerate discharge of the gate of the regulating transistor of the LDO.
The transient enhancement circuit of the embodiment generates gradually increasing and gradually decreasing Under _ Signal and Over _ Signal signals respectively when the output load current suddenly increases or suddenly decreases, and is used for controlling the charging and discharging of the slew rate enhancement circuit to the adjusting tube. Since it does not operate in steady state, the quiescent current is very low. When the circuit is in a dynamic state, the circuit is only operated for a period of time, so that the power consumption of the circuit is greatly reduced while the transient response speed is enhanced.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that an article or device that comprises a list of elements does not include only those elements but may include other elements not expressly listed. Without further limitation, an element defined by the phrases "comprising one of \8230;" does not exclude the presence of additional like elements in an article or device comprising the element. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect.
The foregoing is a further detailed description of the invention in connection with specific preferred embodiments and it is not intended to limit the invention to the specific embodiments described. For those skilled in the art to which the invention pertains, numerous simple deductions or substitutions may be made without departing from the spirit of the invention, which shall be deemed to belong to the scope of the invention.

Claims (6)

1. A transient enhancement circuit for a low power LDO, comprising: an overshoot detection circuit, a negative slew rate enhancement control signal generation circuit, a positive slew rate enhancement control signal generation circuit, and a slew rate enhancement circuit, wherein,
the input end of the overshoot detection circuit is connected with the output end of the LDO, the first output end of the overshoot detection circuit is connected with the input end of the negative slew rate enhancement control signal generation circuit, and the second output end of the overshoot detection circuit is connected with the input end of the positive slew rate enhancement control signal generation circuit;
the output end of the negative slew rate enhancement control signal generation circuit and the output end of the positive slew rate enhancement control signal generation circuit are both connected with the input end of the slew rate enhancement circuit; the output end of the slew rate enhancement circuit is connected with an adjusting tube of the LDO;
the overshoot detection circuit is used for detecting the output voltage of the LDO and generating an undershoot detection signal (VSEN _ P) and an overshoot detection signal (VSEN _ N) when the output voltage of the LDO jumps;
the negative slew rate enhancement control Signal generating circuit generates a negative slew rate enhancement control Signal (Under _ Signal) according to the undershoot detection Signal (VSEN _ P) when the output voltage of the LDO undershoots;
the positive slew rate enhancement control Signal generation circuit generates a positive slew rate enhancement control Signal (Over _ Signal) according to the overshoot detection Signal (VSEN _ N) when the output voltage of the LDO is overshot;
the slew rate enhancement circuit controls the grid electrode of an adjusting tube of the LDO to be charged and discharged quickly according to the received negative slew rate enhancement control Signal (Under _ Signal) or the positive slew rate enhancement control Signal (Over _ Signal) so as to realize the quick transient response of the LDO;
wherein, the overshoot detection circuit comprises a first capacitor (C1), a second capacitor (C2), a first MOS transistor (M1), a second MOS transistor (M2), a third MOS transistor (M3) and a fourth MOS transistor (M4), wherein,
the source electrode of the first MOS tube (M1) inputs an external P tube BIAS voltage (V _ BIAS _ P), and the grid electrode of the first MOS tube (M1) is respectively connected with the drain electrode of the first MOS tube and the grid electrode and the source electrode of the second MOS tube (M2);
the source electrode of the fourth MOS tube (M4) inputs an external N tube BIAS voltage (V _ BIAS _ N), and the grid electrode of the fourth MOS tube (M4) is respectively connected with the drain electrode of the fourth MOS tube and the grid electrode and the source electrode of the third MOS tube (M3);
the drain electrode of the second MOS tube (M2) is used as a first output end of the overshoot detection circuit to output the undershoot detection signal (VSEN _ P); the drain electrode of the third MOS tube (M3) is used as a second output end of the overshoot detection circuit to output the overshoot detection signal (VSEN _ N);
the first capacitor (C1) is connected in series between the output end of the LDO and the drain electrode of the second MOS tube (M2); the second capacitor (C2) is connected in series between the output end of the LDO and the drain electrode of the third MOS tube (M3).
2. The transient enhancement circuit for low power LDO of claim 1, wherein when the regulating transistor of the LDO is a pMOS transistor, the negative slew rate enhancement control signal generating circuit comprises: a third capacitor (C3), a fifth MOS tube (M5), a sixth MOS tube (M6), a seventh MOS tube (M7), an eighth MOS tube (M8), a ninth pMOS tube (Mp 9), a tenth pMOS tube (Mp 10), an eleventh MOS tube (M11), a twelfth MOS tube (M12) and a thirteenth MOS tube (M13), wherein,
the source electrode of the fifth MOS transistor (M5), the source electrode of the seventh MOS transistor (M7) and the source electrode of the ninth pMOS transistor (Mp 9) are all connected with a power supply end (VDD);
the grid electrode of the fifth MOS tube (M5) is connected with the first output end of the overshoot detection circuit, the drain electrodes of the fifth MOS tube (M5) and the sixth MOS tube (M6) are respectively connected with the drain electrode of the seventh MOS tube (M7), the grid electrode of the eighth MOS tube (M8), the grid electrode of the tenth pMOS tube (Mp 10) and the grid electrode of the twelfth MOS tube (M12);
the grid electrode of the sixth MOS tube (M6) inputs the BIAS voltage (V _ BIAS _ N) of the external N tube;
the drain electrode of the seventh MOS tube (M7) is respectively connected with the drain electrode of the eighth MOS tube (M8) and the grid electrode of the eleventh MOS tube (M11);
the grid electrode of the ninth pMOS tube (Mp 9) inputs the BIAS voltage (V _ BIAS _ P) of the external P tube, and the drain electrode of the ninth pMOS tube (Mp 9) is connected with the source electrode of the tenth pMOS tube (Mp 10);
the drain electrode of the tenth pMOS tube (Mp 10) is respectively connected with the source electrode of the eleventh MOS tube (M11), the drain electrode of the twelfth MOS tube (M12) and the gate electrode of the thirteenth MOS tube (M13);
the drain electrode of the eleventh MOS tube (M11) is respectively connected with the source electrode of the twelfth MOS tube (M12), the drain electrode of the thirteenth MOS tube (M13) and the second input end of the slew rate enhancement circuit;
the third capacitor (C3) is connected between the drain electrode of the tenth pMOS tube (Mp 10) and a ground terminal (GND) in series;
the source electrode of the sixth MOS transistor (M6), the source electrode of the eighth MOS transistor (M8) and the source electrode of the thirteenth MOS transistor (M13) are all connected with the ground terminal (GND).
3. The transient enhancement circuit for the low power LDO according to claim 2, wherein the slew rate enhancement control signal generating circuit comprises a fourth capacitor (C4), a fourteenth MOS transistor (M14), a fifteenth MOS transistor (M15), a sixteenth MOS transistor (M16), a seventeenth MOS transistor (M17), an eighteenth NMOS transistor (Mn 18), a nineteenth NMOS transistor (Mn 19), a twentieth MOS transistor (M20), a twenty-first MOS transistor (M21) and a twenty-second MOS transistor (M22), wherein,
the source electrode of the fourteenth MOS transistor (M14), the source electrode of the sixteenth MOS transistor (M16) and the source electrode of the twelfth MOS transistor (M22) are all connected with the power supply end (VDD);
the gate of the fourteenth MOS tube (M14) inputs the external P tube BIAS voltage (V _ BIAS _ P), and the drain is respectively connected with the drain of the fifteenth MOS tube (M15), the gate of the sixteenth MOS tube (M16), the gate of the seventeenth MOS tube (M17), the gate of the eighteenth nMOS tube (Mn 18) and the gate of the twentieth MOS tube (M20);
the grid electrode of the fifteenth MOS tube (M15) is connected with the second output end of the overshoot detection circuit;
the drain electrode of the sixteenth MOS transistor (M16) is respectively connected with the drain electrode of the seventeenth MOS transistor (M17) and the grid electrode of the twenty-first MOS transistor (M21);
the gate of the nineteenth nMOS tube (Mn 19) inputs the external N tube BIAS voltage (V _ BIAS _ N), and the drain is connected with the source of the eighteenth nMOS tube (Mn 18);
the drain electrode of the eighteenth nMOS transistor (Mn 18) is respectively connected with the source electrode of the twentieth MOS transistor (M20), the drain electrode of the twenty-first MOS transistor (M21) and the gate electrode of the twenty-second MOS transistor (M22);
the drain electrode of the twentieth MOS transistor (M20) is respectively connected with the source electrode of the twenty-first MOS transistor (M21), the drain electrode of the twenty-second MOS transistor (M22) and the first input end of the slew rate enhancement circuit;
the fourth capacitor (C4) is connected in series between the drain electrode of the eighteenth nMOS transistor (Mn 18) and the power supply end (VDD);
the source electrode of the fifteenth MOS tube (M15), the source electrode of the seventeenth MOS tube (M17) and the source electrode of the nineteenth nMOS tube (Mn 19) are all connected with the grounding end (GND).
4. The transient enhancement circuit for low power consumption LDO of claim 1, wherein when the regulating transistor of the LDO is an nMOS transistor, the negative slew rate enhancement control signal generating circuit comprises: a third capacitor (C3), a fifth MOS transistor (M5), a sixth MOS transistor (M6), a seventh MOS transistor (M7), an eighth MOS transistor (M8), a ninth nMOS transistor (Mn 9), a tenth nMOS transistor (Mn 10), an eleventh MOS transistor (M11), a twelfth MOS transistor (M12) and a thirteenth MOS transistor (M13), wherein,
the source electrode of the fifth MOS transistor (M5), the source electrode of the seventh MOS transistor (M7) and the source electrode of the thirteenth MOS transistor (M13) are all connected with a power supply end (VDD);
the grid electrode of the fifth MOS tube (M5) is connected with the first output end of the overshoot detection circuit, the drain electrodes of the fifth MOS tube (M5) are respectively connected with the drain electrode of the sixth MOS tube (M6), the grid electrode of the seventh MOS tube (M7), the grid electrode of the eighth MOS tube (M8) and the grid electrode of the twelfth MOS tube (M12);
the grid electrode of the sixth MOS tube (M6) inputs the BIAS voltage (V _ BIAS _ N) of the external N tube;
the drain electrode of the seventh MOS transistor (M7) is respectively connected with the drain electrode of the eighth MOS transistor (M8), the gate electrode of the ninth nMOS transistor (Mn 9) and the gate electrode of the eleventh MOS transistor (M11);
the grid electrode of the tenth nMOS tube (Mn 10) inputs the external N tube BIAS voltage (V _ BIAS _ N), and the drain electrode of the tenth nMOS tube (Mn 10) is connected with the source electrode of the ninth nMOS tube (Mn 9);
the drain electrode of the ninth nMOS transistor (Mn 9) is respectively connected with the source electrode of the eleventh MOS transistor (M11), the drain electrode of the twelfth MOS transistor (M12) and the gate electrode of the thirteenth MOS transistor (M13);
the drain electrode of the eleventh MOS tube (M11) is respectively connected with the source electrode of the twelfth MOS tube (M12), the drain electrode of the thirteenth MOS tube (M13) and the first input end of the slew rate enhancement circuit;
the third capacitor (C3) is connected in series between the drain of the ninth nMOS transistor (Mn 9) and the power supply terminal (VDD);
and the source electrode of the sixth MOS transistor (M6), the source electrode of the eighth MOS transistor (M8) and the source electrode of the tenth nMOS transistor (Mn 10) are all connected with a ground terminal (GND).
5. The transient enhancement circuit for the low power LDO according to claim 4, wherein the slew rate enhancement control signal generating circuit comprises a fourth capacitor (C4), a fourteenth MOS transistor (M14), a fifteenth MOS transistor (M15), a sixteenth MOS transistor (M16), a seventeenth MOS transistor (M17), an eighteenth pMOS transistor (Mp 18), a nineteenth pMOS transistor (Mp 19), a twentieth MOS transistor (M20), a twenty-first MOS transistor (M21) and a twenty-twelfth MOS transistor (M22), wherein,
the source electrode of the fourteenth MOS tube (M14), the source electrode of the sixteenth MOS tube (M16) and the source electrode of the eighteenth pMOS tube (Mp 18) are all connected with the power supply end (VDD);
the grid electrode of the fourteenth MOS tube (M14) inputs the BIAS voltage (V _ BIAS _ P) of the external P tube, and the drain electrode of the fourteenth MOS tube is respectively connected with the drain electrode of the fifteenth MOS tube (M15), the grid electrode of the sixteenth MOS tube (M16), the grid electrode of the seventeenth MOS tube (M17) and the grid electrode of the twentieth MOS tube (M20);
the grid electrode of the fifteenth MOS tube (M15) is connected with the second output end of the overshoot detection circuit;
the drain electrode of the sixteenth MOS transistor (M16) is respectively connected with the drain electrode of the seventeenth MOS transistor (M17), the gate electrode of the nineteenth pMOS transistor (Mp 19) and the gate electrode of the twenty-first MOS transistor (M21);
the gate of the eighteenth pMOS tube (Mp 18) inputs the external P tube BIAS voltage (V _ BIAS _ P), and the drain is connected with the source of the nineteenth pMOS tube (Mp 19);
the drain electrode of the nineteenth pMOS tube (Mp 19) is respectively connected with the source electrode of the twentieth MOS tube (M20), the drain electrode of the twenty-first MOS tube (M21) and the gate electrode of the twenty-second MOS tube (M22);
the drain electrode of the twentieth MOS transistor (M20) is respectively connected with the source electrode of the twenty-first MOS transistor (M21), the drain electrode of the twenty-second MOS transistor (M22) and the second input end of the slew rate enhancement circuit;
the fourth capacitor (C4) is connected in series between the drain of the nineteenth pMOS tube (Mp 19) and the ground terminal (GND);
the source electrode of the fifteenth MOS tube (M15), the source electrode of the seventeenth MOS tube (M17) and the source electrode of the twelfth MOS tube (M22) are all connected with the grounding terminal (GND).
6. The transient enhancement circuit for a low-power LDO according to claim 2 or 4, wherein the slew rate enhancement circuit comprises twenty-three MOS transistors (M23) and twenty-four MOS transistors (M24), wherein,
a source electrode of the twenty-third MOS transistor (M23) is connected with the power supply end (VDD), a grid electrode is used as a first input end of the slew rate enhancement circuit, and a drain electrode of the twenty-third MOS transistor is connected with a drain electrode of the twenty-fourth MOS transistor (M24) and a grid electrode of an adjusting transistor of the LDO respectively;
and the source electrode of the twenty-four MOS tube (M24) is connected with the grounding end (GND), and the grid electrode is used as a second input end of the slew rate enhancement circuit.
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